Question

The points (30, 50). (-10, 30) and (-20, s) all lie on the same line. What is the value of s? Show your work.

Answer 1

s = 25

Explanation:

First we go from point (30, 50) to point (-10, 30).

Change in x: -10 - 30 = -40

Change in y: 30 - 50 = -20

Since a change in x of -40 results in a change in y of -20, we divide both changes by 4 to get:

a change of -10 in x results in a change of -5 in y.

Now we go from point (-10, 30) to point (-20, s).

The change in x is -20 - (-10) = -10

The corresponding chang ein y must be -5.

y = 30 - 5 = 25

Answer: s = 25